It should startle no one that the prolific Naylor (the Alice books) should continue the boy-and-his-dog story begun in her Newbery Medal winner Shiloh--nor will fans be startled that Naylor maintains the previous work's lump-in-the-throat vibrato. As the novel begins, Marty Preston relishes the companionship of his beagle, Shiloh, at last protected from the abuses of his former owner, Judd Travers. But Marty's happiness is shadowed by doubts about the way he acquired the dog--through a combination of honest work and outright blackmail. When Judd takes to drinking and then to hunting on the Prestons' property, Marty worries that Judd will target Shiloh as his prey. Marty's conflicts are a bit more labored here than in the previous book, but Naylor so perceptively conveys the strength of his affections and the scope of his fears that she amply compensates for narrative shortcomings. She broadens the West Virginia setting to show Marty at school; in an especially graceful moment, Marty's teacher takes him aside and gently explains the different roles of ""family talk"" (i.e., Marty's vernacular) and grammatical speech. The author's sympathy for her characters, both the good guys and those who menace them, communicates itself almost invisibly to the reader, who may well come away hoping for a full-fledged Shiloh series. Ages 8-12. (Sept.)